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Black hole

Sagittarius A*

Sagittarius A* is the supermassive black hole at the center of the Milky Way, with a mass of about four million times that of the Sun.

Verified 2026-10-02
Center of the Milky Way with Sagittarius A*.
Type: Image · scientific illustration Provider: NASA Author: NASA/JPL-Caltech/ESA/C. Carreau Credit: Credit: NASA/JPL-Caltech/ESA/C. Carreau Licence: NASA Image Use Policy Colour treatment: illustrated

Overview

Sagittarius A* is the supermassive black hole at the center of the Milky Way. It is part of the central structure of our home galaxy, where the orbits of several stars established that a supermassive black hole is present. Its mass is about four million times the mass of the Sun.

Black holes are extremely dense concentrations of matter. Their event horizons are boundaries inside which gravity is so strong that nothing, including light, can escape. A black hole does not emit or reflect light, but it can be studied through its effects on nearby material and stars. Bright flares and fainter flickers have been detected from Sagittarius A*; their rapid changes indicate an origin very close to the black hole.

Essential data

Key fact
It is located at the center of the Milky Way.
Key fact
It is a supermassive black hole.
Key fact
Its mass is about four million times the Sun’s mass.
Key fact
Nearby stellar orbits established the presence of a supermassive black hole at the galactic center.
Key fact
Bright flares and fainter flickers have been detected from Sagittarius A*.

Sources and references

  1. Black Hole Basics NASA Science